Facebook and YouTube are separate.
If you have a YouTube channel, consider ALSO uploading the video to Facebook.
The way people share videos is a bit different for both. Example this is what I do with:
Facebook video, hit share and share on my page or profile so MANY people see it.
YouTube video, hit share, copy the link or send direct to text someONE. (IF I even share it).
People are searching for information on YouTube just like they do on Google. Facebook search? It’s possible, however not like Google.
Both serve a purpose to promote the goodness that you’re sharing separately.